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Old May 05, 2010, 05:54 PM
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Meridian Idaho
Joined Feb 2010
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First Post And Build Log: Guillows Stearman PT-17

Preamble - Little to do with build

Hello,
Over the past few years, I have been finding that I really want to build\make things. I have tried a number of things to a certain degree of success. I tried wood carving, I built a Barbie ferris wheel, started work on a Barbie rollercoaster, built a simple electric motor and then contemplated buiding a electric bike. Nothing was really hitting the 'I am enjoying building this' spot in my brain.

Not long ago, a HobbyLobby opened up just a few short miles away from my home so I dropped by to look around. While looking through the hobby area, I came across a box labeled 'Guillow Cessna 170'. I thought it was really expensive, $19 and I almost didnt buy it till I found out that it was on sale. I ended up buying it for $12.

I loved building it. It hit about every different area of the 'need to build' spot in my brain. If I didnt want to think much, I could just follow the plans. If I wanted to create something different or improvise, well balsa just happens to be a excellent medium for playing around. On top of it all, and best of all for a guy raised on tv and video games, I COULD USE SUPER GLUE. 5 seconds and I am on to the next thing.

I put it together and started looking around the internet for other kits and found RCGroups. It was here that I started reading the build logs detailing how to make these kits fly. I had to try. I hit my first roadblock right away, cost. I went to the local hobby stores and found out that to get up and going with a basic RC plane, it was going to be $200. Not going to happen. Then I found HK and for less than $50, had everything I needed to try an convert my Guillow Cessna 170 to a electric RC plane.

It took me a long time to put it together with everything needed to try my first flight. It took about 4 seconds for my little Cessna crash and break apart. It didnt bother me. I will get something to fly, someday. This just started the gears tumbling. I bought a House Of Balsa 1/12 scale P-51. It flew for 5 seconds before crashing and busting the wing off.

This last flight leaves me where I am today. The crashed Cessna 170 didnt get repaired. Instead, I took the wings and stabilizers and build a simple little box body for them. My next attempt at flight will be with this. The P-51 was easy to repair but I dont want to try and fly it again until I have flown something else successfully.

I have some flying to do but I still need to build things so I thought I would make some build logs. I am sure, if I am able to track a build start to finish, that some usefull information will be shared but I also could really use the help of those who have done this before.

I started off my balsa bit building attempts by purchasing the following kits:

Guillows Sopwith Camel (28 inch wingspan)
Guillows Stearman PT-17 (28 inch wingspan)
Guillows Curtiss P-40 Warhawk (27 inch wingspan)
Sterling P-61 Black Widow (38 inch wingspan)
Sterling De Havilland Tiger Moth (33 inch wingspan)
Golden Age Reproduction Fairchild Ranger Seaglen (30 inch wingspan)
Dare Hobby De Havilland Mosquito (40 inch wingspan)

When I received the Sterling kits, (especially the Tiger Moth) I was surprised at how poor the balsa and the stamping are. The P-61 isnt to bad but the Tiger Moth definetly deserves the name 'die crushed'. I am going to wait a bit on those.

I think my build order will be the following. Guillows Stearman PT-17, Guillows P-40, Guillows Sopwith Camel, GAR Farchild Ranger, Sterling Tiger Moth, Sterling Black Widow, De Havilland Mosquito.

So, First up, by request of my 9 year old daughter, the Stearman PT-17.

I will make A LOT of mistakes and I plan to highlight those as much as anything.
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Old May 05, 2010, 06:06 PM
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Meridian Idaho
Joined Feb 2010
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Build So Far

So Far, I have the fuselage mostly assebled, the top wing mostly assembled and the bottom wing partially assembled.

Here are the electronics components I have so far:

Motor: Power Up 2712-12 Outrunner Brushless Electric Motor (25 grams)
ESC: MAG 8 18A ESC .8 oz roughtly 22 grams
Battery: 800 mah 2 cell lipo (43 grams)
Hobby King Receiver (18 grams)
3 5g TP SG50 servos (15 grams)

I will include some pictures as soon as I can get them off my camera.
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Old May 05, 2010, 08:10 PM
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Albuquerque, NM USA
Joined Sep 2003
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Welcome to the forum and especially building.

As you have noticed, building and flying a scale model is not quite as easy as it might look.

I'd recommend you go to Stevens Aero or Mountain Models and get a kit for learning to fly. Many to choose from and at least one that would work with your current electric system. MM or Stevens 'stick' would be a good place to start. And, they are enough fun to keep long after you move into scale stuff.

For a first scale flying plane I also like to recommend the MM C-180, designed by Dave Blum.

Meanwhile you can build and detail the Stearman so it is ready to fly when your skills are up to it.

charlie
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Old May 05, 2010, 08:24 PM
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Everett Wa.
Joined Jun 2001
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I'd like to add my welcome.

I have to ask, do you know how to fly R/C aircraft? And if so what is your level of competency?

It has been stated that building and flying scale is not easy, in fact it is a rather advanced skill set within the R/C flying community.

I whole heartily agree with Charlie's recommendation for a first scale build a MM C-180.

http://www.mountainmodels.com/produc...roducts_id=228

The kits you list are very advance and not designed to be built as Electric R/C aircraft. While they often do make great conversions there is little in the kit that would guide one to a successful conclusion.

While the MM C-180 might seem a bit steep in price, compared to what you paid for the rubber band powered kits, it really is a great value as the final product will fly.

I hope you have seen this thread on how to build the Guillow's kits.

http://www.rcgroups.com/forums/showthread.php?t=827861

All the best,
Konrad

I'd like to point you to the thread on how to lighten model structures.
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Last edited by Konrad; May 05, 2010 at 08:34 PM.
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Old May 05, 2010, 11:39 PM
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United States, CA, Garden Grove
Joined Oct 2000
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Hey Goomba! Please, please, read over this thread where a nice guy in Kilkenny Ireland , with little building and flying experience, despite a lot of good advice to start with something simpler, decided to build the same Guillows PT-17 as his first built-up electric powered scale RC model. BTW, he was not the only beginner to struggle building this small complicated rubber-powered free flight model as an electric powered R/C model.

Tageus was given a lot of advice and encouragement on this forum, and eventually acheived a few seconds of semi-controlled flight after a number of attempted maiden flights and a lot of crash repairs an frustration. In the process, he learned quite a lot about building "stick models", choosing power system components, strategic location of power and RC components as needed to achieve proper center of gravity, wing incidence, motor thrust angles, etc and surviving a number of attempts at controllable flight including crash repairs and changes and one short nearly successful flight.


http://www.rcgroups.com/forums/showthread.php?t=1035417
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Old May 06, 2010, 09:08 AM
MPP
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Danbury CT (DXR)
Joined Oct 2005
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Hey Goomba, good for you to catch the building bug. As these great builders have stated you have a list of some challenging conversions.

I would also like to suggest a good flight simulator. These prove to be worth every cent when you consider not only only the equipment investment but your time investment.

The reset button gives you a whole new model to fly in an instant. Probably the best way to go for a do it yourselfer.

Good luck

Mark
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Old May 06, 2010, 10:33 AM
Kansas is windy.
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Wichita, KS
Joined Jun 2003
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Goomba,

I'll second all the advice so far on this! Building and flying are two different skill sets. The FMS flight simulator is free- you can get a cable to connect your transmitter to your computer for this on ebay cheap, and this will include the software also.

I will also recommend getting an inexpensive "foamy" airplane to fly now and build up your flying skills. The best thing about these is you can rebuild in one evening after a crash. In the mean time you can build your wood model and then use the components from the foamy when you are done.

FWIW, I converted the Guillows Stearman and it was a great success. Mainly I can contribute this success to significant lightening of the airframe resulting in a low flying weight. Here is my thread: http://www.rcgroups.com/forums/showthread.php?t=272230

Good Luck with whatever you do.
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Old May 06, 2010, 10:48 AM
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USA, FL, Tampa
Joined Jul 2002
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I too welcome you to the forums and the wonderful addiction of converting these models to rc.

You picked a challenging model for sure and the advice given above about says it all.
Jug jock had a similar experience to Tageus with this model and his build thread is here somewhere and would be a recommended read.

I built the Sterling P-61 from plans and it was not an easy conversion. It is a decent flying model but could use a bit more speed. Maybe someday I'll upgrade the power system and give it the horsepower it deserves.

Glenn
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Old May 06, 2010, 12:08 PM
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Meridian Idaho
Joined Feb 2010
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Awesome,
Thanks. I have read through all the above mention threads. Read through the build log by Tageus a couple of times. I am not sure what my expectations are but I don’t plan on flying this one right off the bat. Its the build that drives me. I don’t think building static models has a satisfying enough end of project. It just seems like successful \ failed first flight is a perfect way to conclude a build. I have read through just about all the Guillows build logs and the ‘how to’

I do agree that I will be setting up myself for major disappointment if I expect to be flying these models right away. After my experiment with the Guillow Cessna 170, I took the wings and stabilizers and built a box around them. Its fairly strong and no heavier than the Cessna. Its about 185 grams with everything on board. My daughters have been pestering me to go crash it. They stopped using the word ‘fly’ after the first attempt. It seems like exploding balsa gives them much joy. They did name it. Its ‘Flying Bob’
I am going to try flying that a couple of times. If that ends up being more than I can handle, a local hobby store has the GWS Slow Stick for $28 that I will try. Will have to add ailerons to it though. My HOB P-51 doesn’t have a rudder and I want to practice flying without a rudder some.

For the most part all the kits that I have all came from Ebay and I paid less than $20 for. The GAR Fairchild and the P-40 were less than $10 (The P-40 had its horizontal stabilizer already built). The box of the Stearman was really beat up and the plywood (balsa is ok) is all warped so I wont be to worked up if they end up a mess. The only one I paid a little more for was the Sterling P-61 and the Mosquito was a B-day present. That’s why I have the P-61 and the Mosquito at the bottom of my build order. I really want to have done this a number of times before I try them. The instructions for the Mosquito are VERY sparse. I may slip a few more kits before them if I find some for cheap. I definitely wont be paying the $45 (that’s what the Stearman costs locally) for the Guillow kits that the hobby store is selling them for. Egad.

Back to the my build. I am actually already having doubts that my PT-17 will ever fly. I have messed up a number of things and to fix 1 of them would require me to rebuild the wings from scratch.

The first picture here is of the fuselage. I thought it had turned out ok till I test fit the lower wing. Obviously, I am having trouble getting the formers attached at a 90% angle.

The second picture shows an example of the formers my Dremmel attack. Shaved them down a fair amount. Its was during this process that I learned that you need to make sure your brushes on your Dremmel are in good shape. A slower Dremmel speed combined with the sanding wheel catching on a former leads to a fairly explosive shattering of said former. Lesson learned, get new brushes and be careful around corners.

The third picture is of my fuselage mess up. The former is angled slightly forward and as a result, the wing will not fit on. Not sure how I am going to fix it at the moment.

The forth picture is a prime example of a beginner mistake on the upper wing. I suspect its fairly easy for everyone to see. I am not sure what this mess up really means and if I am going to need to re-build the wings. (if you cant see the error, examine the leading edge) .

The final picture is of both wings. The bottom wing is a semi mess. For some reason, after gluing the 3 parts of the bottom wing together, one side is staying up the required ¾ inch. The other side wasn’t. So I tried to use the stringers to fine tune the dihedral (I think that’s the correct term). Problem is I got confused on which wing needed fixing so now I have 1 wing tip that is to low and 1 that is to high.

One other mess up deals with sanding. I need to be careful with the stringers when sanding. I was focusing on sanding some rough edges on a rib and pretty much sanded a stringer all the way through.

These pictures are completely messed up. I emailed them to work and for some reason outlook decided to resise them to thumbnails when I put them in the e-mail. I sized them back up but they are still pretty poor. Re up them later.
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Old May 06, 2010, 12:11 PM
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Forgot to mention this, I have not successfully flown something as of yet.
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Old May 06, 2010, 12:17 PM
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One other quick note. I have been on-line for a long time and have developed a fairly thick skin. Feel free to call me a doofus when I am being a doofus. I have no problem with criticism, constructive or otherwise.
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Old May 06, 2010, 12:29 PM
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Everett Wa.
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Is the wing flaw that the LE was pinned down with the long dimension down? It shouldn't be to much of an issue to free the ribs and re-glue the LE with the long dimension upwards.

All the best,
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Old May 06, 2010, 01:29 PM
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Meridian Idaho
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Quote:
Originally Posted by Konrad View Post
Is the wing flaw that the LE was pinned down with the long dimension down? It shouldn't be to much of an issue to free the ribs and re-glue the LE with the long dimension upwards.

All the best,
Yeah, the funny thing is that I did it correctly on the 2 models that I built previously. I will be working on that tonight. I am hoping that I can change it without busting things. The top wing shouldnt be to bad. Perhaps when I fix the lower wing, I can use that opportunity to correct the problems with the dihedral (I think thats the term) where the left wing tip is about 1/4 inch higher than the right.
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Old May 07, 2010, 11:32 AM
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Meridian Idaho
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Fixing the leading edge on the lower wing was interesting. Removing it was fairly straight forward.

The lower wing is basically 3 sections. Left wing, right wing and a center section that is about 2 inches wide. If the center section is flat against the working surface, the wing tips are supposed to be 3/4 of an inch above the working surface. When you assemble it, you assemble it with the wing flat and then raise the tips before adding the srtingers. To fix the leading edge problem, I removed the existing edge and then used duct tape to secure the wings to the surface. The problem that I ran into was that after removing the old leading edge, a lot of the ribs flexed and moved out of position.

Needless to say, there was some extra tension when I attached the new edge. WHen I removed the duct tape, the edge on one wing popped off in a rather explosive fassion. I would guess it made it 6 feet or more from the table. I ended up removing some stringers and then repeated the process. Its together and holding now.

For the top wing I decided that removing the LE was more complicated than necessary so I just added a strip of balsa to the bottom of the edge to the LE is now a square. Will just require a little extra sanding. The dremmel will make that a non-issue.

For the out of place former, moving the existing former just isnt going to work. Tonight, I am going to create a new former and glue it in behind the existing one and then cut the existing one out.
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Old May 07, 2010, 12:30 PM
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I knew you would figure out easy some fixes. As a general suggestion, carefully study the plans and read and understand the instructions a couple of times before starting assembly. Try to identify steps that will have to be done in a certain order especially those involving installation of servos, motor, battery, speed control and receiver. This model has a very short nose. In order to get the model to balance fore and aft properly, you will need to plan and provide for mounting everything as far toward the nose as practical and you will still have to add weight to the nose to get the cg in the right place for controllable flight. You will need to decide how to mount the upper wing and how to attach the N struts. Both wings will need to be "level" i,e., wing leading edge not pointed up with respect to the fuselage. You can save weight and complexity by not installing ailerons. Installing ailerons using two tiny servos and a Y cable is not difficult but the weight is a problem with such a small model. You will also need to mount the motor so that it's shaft points a little to the right and a little downward, (just noticeable down and right thrust). Your wings and tail sirfaces cannot have any unwanted twists or warps although the tips of each wing should have a little "washout" trailing/rear edge of each wing raised about 1/8". You can add a little washout during shrinking of the wings covering. Recommend you use a light weight iron-on covering like Coverrite Microlite from Hobby People. You will need to make a plywood firwall with blind nuts to mount the motor you intend to use. Your choice of battery pack, motor and speed control should be done carefully. I recommend a "low kv" brushless outrunner type motor that can swing a 7-8" prop and provide adequate power with an 800mah lipo battery for five to 7 minutes flight time at 1/2 to 2/3 throttle. Some of the other members can give better power system recommendations. I don't like to use tiny geared brushed in-runner motors anymore though some love them for models like this. Important: You will need to provide a large enough compartment for the battery pack right behind the firewall. Try to keep the fuselage from developing a "banana" shape by installing corresponding stringers on each side. The stringer notches in the formers may not line up properly, renotch them as needed with Dremel tool and a flat grinding disc ( use fibreglass reinforced ones, they don't shattter and bust your safety glasses.)
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